DS75LVU+ Maxim Integrated Products, DS75LVU+ Datasheet - Page 6

• Manufacturer Part Number: DS75LVU+
• Description: IC SENSOR TEMP DIGITAL 8MSOP
• Manufacturer: Maxim Integrated Products

Specifications of DS75LVU+

• Function: Thermometer, Thermostat
• Topology: ADC (Sigma Delta), Comparator, Register Bank
• Sensor Type: Internal
• Sensing Temperature: -55°C ~ 125°C
• Output Type: I²C™/SMBus™
• Output Alarm: No
• Output Fan: No
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Temperature Threshold: Programmable
• Full Temp Accuracy: +/- 2 C
• Digital Output - Bus Interface: 2-Wire, SMBus
• Digital Output - Number Of Bits: 9 bit to 12 bit
• Supply Voltage (max): 3.7 V
• Supply Voltage (min): 1.7 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Supply Current: 1000 uA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DS75LV: Digital Thermometer and Thermostat
OPERATION⎯THERMOSTAT
The DS75LV thermostat has two operating modes, comparator mode and interrupt mode, which activate and
deactivate the open-drain thermostat output (O.S.) based on user-programmable trip-points (T
and T
). The
OS
HYST
DS75LV powers up with the thermostat in comparator mode, active-low O.S. polarity, over-temperature trip-point
(T
) register set to 80 C, and the hysteresis trip-point (T
) register set to 75ºC. If these power-up settings are
OS
HYST
compatible with the application, the DS75LV can be used as a standalone thermostat (i.e., no 2–wire
communication required). If interrupt mode operation, active-high O.S. polarity or different T
and T
values are
OS
HYST
desired, they must be programmed after power-up, so standalone operation is not possible.
In both operating modes, the user can program the thermostat fault tolerance, which sets how many consecutive
temperature readings (1, 2, 4, or 6) must fall outside of the thermostat limits before the thermostat output is
triggered. The fault tolerance is set by the F1 and F0 bits in the configuration register. At power-up the fault
tolerance is set to 1.
The data format of the T
and T
registers is identical to that of the temperature register (see Figure 3), i.e., a
OS
HYST
two-byte two’s complement representation of the trip-point temperature in degrees centigrade with bits 3 through 0
hardwired to 0. After every temperature conversion, the measurement is compared to the values stored in the T
OS
and T
registers. The O.S. output is updated based on the result of the comparison and the operating mode of
HYST
the IC. The number of T
and T
bits used during the thermostat comparison is equal to the conversion
OS
HYST
resolution set by the R1 and R0 bits in the configuration register. For example, if the resolution is 9 bits, only the 9
MSbs of T
and T
will be used by the thermostat comparator.
OS
HYST
The active state of the O.S. output can be changed via the POL bit in the configuration register. The power-up
default is active low.
If the user does not wish to use the thermostat capabilities of the DS75LV, the O.S. output should be left floating.
Note that if the thermostat is not used, the T
and T
registers can be used for general storage of system data.
OS
HYST
Comparator Mode: When the thermostat is in comparator mode, O.S. can be programmed to operate with any
amount of hystoresis. The O.S. output becomes active when the measured temperature exceeds the T
value a
OS
consecutive number of times as defined by the F1 and F0 fault tolerance (FT) bits in the configuration register. O.S.
then stays active until the first time the temperature falls below the value stored in T
. Putting the device into
HYST
shutdown mode does not clear O.S. in comparator mode. Thermostat comparator mode operation with FT = 2 is
illustrated in Figure 4.
Interrupt Mode: In interrupt mode, the O.S. output first becomes active when the measured temperature exceeds
the T
value a consecutive number of times equal to the FT value in the configuration register. Once activated,
OS
O.S. can only be cleared by either putting the DS75LV into shutdown mode or by reading from any register
(temperature, configuration, T
, or T
) on the device. Once O.S. has been deactivated, it will only be
OS
HYST
reactivated when the measured temperature falls below the T
value a consecutive number of times equal to the
HYST
FT value. Again, O.S can only be cleared by putting the device into shutdown mode or reading any register. Thus,
this interrupt/clear process is cyclical between T
and T
events (i.e, T
, clear, T
, clear, T
, clear, T
,
OS
HYST
OS
HYST
OS
HYST
clear, etc.). Thermostat interrupt mode operation with FT = 2 is illustrated in Figure 4.
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